Antioxidant activity is an activity that reduces production of reactive oxygen species in the body and at the same time, prevents oxidation that causes irrecoverable damages to cells. Ground-state or triplet oxygen can be activated as a result of exposure to environmental or biochemical factors such as enzymes, reduction metabolism, chemical compounds, pollutants and photochemical reactions, and transformed into reactive oxygen species (ROS) which have a high reactivity such as superoxide radicals, hydroxy radicals, and hydrogen peroxide, accordingly it results in irreversibly disrupting cell constituents. The actions of such reactive oxygen species can be reduced by antioxidant enzymes such as superoxide dismutase(SOD), catalase and peroxidase, and antioxidant substances such as vitamin C, vitamin E and glutathione, which all form the body's defense system. However, where disorder of such a defense mechanism in the body or exposure to excessive reactive oxygen species occurs, reactive oxygen species may irreversibly disrupt lipid, protein and DNA. As a result, various diseases inclusive of aging, cancer, multiple arteriosclerosis, arthritis and Parkinson's disease are caused.
Synthetic antioxidants such as BHA (butylated hydroxy anisole), BHT (butylated hydroxy toluene) and NDGA (nordihydro-guaiaretic acid) have been developed to date. By way of examples of natural antioxidants, there are antioxidant enzymes such as superoxide dismutase, peroxidase, catalase and glutathione peroxidase, and non-enzymatic antioxidant substances such as tocopherol (vitamin E), ascorbic acid (vitamin C), cartenoid and glutathione.
However, synthetic antioxidants may cause allergic reactions and oncogenesis due to their strong toxicity in the body, and be easily disrupted by heat due to temperature sensitivity. On the other hand, natural antioxidants are safer than synthetic antioxidants in the body but have the problem of weak effect. Therefore, the development of a new natural antioxidant having no problem with safety in use and also having excellent antioxidant activity has been required.
Meanwhile, procyanidin is a kind of proanthocyanidin present in various plants, which is known to be safe and have excellent antioxidant activity among natural antioxidants found to date. Proanthocyanidin is a group of compounds with a condensed tannin, that is, flavan-3-ol or flavan-3,4-diol which is bonded as a structural unit by condensation or polymerization. Of those, procyanidin includes all of the polymers ranging from dimers to oligomers of its backbone such as catechin, epicatechin, catechin gallate, epicatechin gallate, gallocatechin gallate or epigallocatechin gallate. Procyanidin is classified into various types according to backbone and bonding style. For example, procyanidin B3 has a catechin-(4α→8)-catechin structure, procyanidin B1 has an epicatechin-(4β→8)-catechin structure, procyanidin B2 has an epicatechin-(4β→8)-epicatechin structure and procyanidin B5 has an epicatechin-(4β→6)-epicatechin structure (Walter Feucht et al., Z. Naturforsch., 54c, 942-945, 1999).
Procyanidin can be obtained by extracting various kinds of plant body with a solvent and fractionating and purifying the extract by chromatography, or can be isolated from wine or beer. Procyanidin was isolated by extraction with a solvent and chromatography from azuk beans (Vigna angularis Ohwiet Ohashi) (Toshiaki Ariga et al., Agricultural Biological Chemistry, Vol. 45, 2709-2712, 1981), bark of pine (Loblolly pine) (R. W. Hemingway et al., Phytochemistry, Vol. 22, 275-281, 1983) and root of knotgrass (Polygonum multiflorum) (Nonaka et al., Phytochemistry, Vol. 21, 429-432, 1982).
It was reported that procyanidin has the ability to bind protein and has anti-inflammatory effect. In particular, it was reported that catechin known as green tea tannin has excellent anticancer effect. U.S. Pat. No. 4,797,421 discloses the antioxidant effect of procyanidin. U.S. Pat. No. 5,646,178 discloses the antibacterial activity of procyanidin isolated from plant materials of the genus Vaccinium, especially cranberries. Korean Patent Application Laid-Open Publication No. 2001-10154 discloses the pharmaceutical composition containing procyanidin as an effective component for prevention or treatment of injury, tumor metastasis, paradental disease and arthritis associated with matrix metalloproteinase. Korean Patent Application Laid-Open Publication No. 1998-702533 discloses an anti-obesity agent containing procyanidin isolated from tamarind seed coat extract as an effective component.
However, until now, there are no reports that Rosa multiflora extract has antioxidant activity and contains procyanidin.